1. Technical Field
The present disclosure relates generally to a portable electronic device having a touch screen and touch keys, and more particularly, to a method and apparatus for controlling a touch-key operation to enhance the convenience of applying a touch input by a pen touch or a finger touch.
2. Description of the Related Art
Recently, touch screens have been widely used in display devices, for allowing a user to input information by directly touching a screen with a finger or an electronic pen. A touch screen is a well-known input means with which a user touches a specific point on a display screen instead of a keyboard, a mouse, or a physical button, so that information about the position of the touched point is input. Thus the touch screen can provide a convenient, intuitive User Interface (UI).
Touch screens are used for portable electronic devices such as a smart phone, a portable phone, a tablet PC, etc. Such a portable device may include dedicated virtual touch keys. The touch keys are a type of UI provided separately from the touch screen to enable a user to intuitively execute a basic function such as menu, back, cancel, etc. through a touch input.
A related art technology involving control of a touch-key operation is disclosed in co-pending Korea Patent Publication No. 10-2012-0015968 (title: “Method and Apparatus for Preventing Touch Malfunction of a Portable Terminal”, inventors: Kim Hee-Duck, Lee Su-Kyong, and Lee Seung-Won, applicant: Samsung Electronics Co., Ltd, and filed on Feb. 22, 2012). That application discloses a technique of preventing a touch malfunction caused by touching a part of a touch screen adjacent to a touch key while also touching the touch key. Specifically, as the part of the touch screen adjacent to the touch key is touched while the touch key is also touched, an operation corresponding to the touch input to the touch screen is performed but a function corresponding to the touch key is not performed. The document discloses a technique of preventing this malfunction.
In related art technology involving control of a touch-key operation, electronic pen inputs are recognized by sensing hovering of the electronic pen, while an operation corresponding to a touch key pressed by a hand is ignored. This technology has been applied to consumer products and prevents errors caused by an unintended palm touch input to a touch key, during input of an electronic pen touch.
FIG. 1 is a plan view of a conventional smart phone device, 10, for which a user manipulates an electronic pen 105 to generate user inputs. FIG. 2 is side view of the device 10 as the user operates it with the electronic pen. A user may unintentionally touch a touch key 168a or 168b at the bottom of a touch screen 190 with his palm while writing on the touch screen 190 with the pen 105. When this happens, the touched key (e.g., the back key 168b) operates unintentionally. Thus a hand touch on one of the touch keys 168a, 168b triggers an unintended operation in many cases while the user writes a note using the electronic pen 105.
To overcome the above problem in a related art solution, when the electronic pen 105 approaches within a hovering recognition distance d of the electronic pen 105, the touch keys 168a, 168b are deactivated. Therefore, even if they're touched under the hovering condition, the touches do not result in corresponding operations and touch malfunction is prevented.
As just described, the touch malfunction caused by a palm touch is more or less mitigated by the technique of ignoring a touch-key operation when sensing hovering of the electronic pen. However, this technique may cause another malfunction as illustrated in FIGS. 3A and 3B: when the user touches the touch key 168a or 168b with his finger to intentionally operate it, and simultaneously holds the electronic pen 105, the pen 105 may be within the hovering recognition distance d. As a consequence, the hovering of the electronic pen is recognized and thus the function of the touch key is not executed. In other words, in the case where the user touches the touch key with his or her finger, and concurrently holds the electronic pen, if the electronic pen enters a hovering recognition area, a user-intended touch-key operation may be ignored.